azizrys

Hi,

I have been having a series of disasters with my 2008 cayenne S for months at this point.
as shown by the title, The nightmare began when I tried to switch on the car and was greeted with the dreadful steering faulty error, which rendered the car useless as I wasn’t able to start it. Long story short the lock had to be broken in order to steer and tow the car out of a tight parking lot. This resulted in a replacement of the steering lock, along with the ECU and immobilizer. The parts were sourced by a ****ty mechanic who apparently got the the new ECU and lock from a base cayenne. My cayenne has PDCC and that is its defining feature imo. Anyways, after the replacement of said parts, the car was giving all sorts of faults, namely:
-WARNING CHASSIS SYSTEM
-PSM FAILURE
the car was also rolling like crazy while cornering, as if PDCC was not in the car. The car was also SIGNIFICANTLY raising ONLY ONE SIDE, usually WELL AFTER a long corner (compensation?) lastly, the car would occasionally not start the engine (only electrical switch on) until the previously mentioned codes showed up on the dash, which means I’d have to wait 10-20 seconds after turning the cars electricity on, and once the faults appeared the engine would start normally, furthermore, it would occasionally start IN 3RD GEAR AND NOT SHIFT AT ALL. This was easy to work around as all I needed to do was switch the car off and back on again, where it would start normally in 2nd gear and shift as it should.

I’ve taken the car to a coding specialist. And according to him the issue is the cars replacement ECU DOESNT RECOGNIZE THE PDCC SINCE IT IS FROM A BASE CAYENNE. im not sure if this is also the cause of the other faults.

One mechanic told me he could get someone to “code PDCC and my cars options into a new motherboard and install that in the replaced ECU”. The specialist tried and it worked for a bit then the faults would come back on. The mechanic mentioned that the ECU kept getting “burned” and that a wiring harness was somehow involved. The crazy part is, after the mechanic tried and basically had given up and told me he doesn’t know what to do (I wasn’t charged) THE CAR WORKED FINE FOR ABOUT A WEEK. NO ROLLING OR RAISING UP OR DOWN….. and now it’s doing the same raising and lowering after corners again. The gear issue and ignition delay + PSM failure errors also completely went away and still haven’t returned, miraculously. But the car basically drives like **** again.

does anyone know wtf is going on ? This issue has cost me time, money, and a whole lot of road rage. Could the issue be mechanical ? Or is it purely a system/software issue? Any input would be highly appreciated.

phatz

I'm not a car expert, but it seems like you've been facing a complex and challenging situation with your 2008 Cayenne S. Based on the information you provided, it's evident that the replacement of the steering lock, ECU, and immobilizer has led to a series of issues, especially related to the PDCC (Porsche Dynamic Chassis Control) system.

Here are a few suggestions and considerations:

1. OEM Parts: Using parts from a base Cayenne might indeed cause compatibility issues, as your car has specific features like PDCC. It's crucial to ensure that the replacement parts are compatible with the features of your Cayenne S.
   
2. Coding and Programming: The attempt to code PDCC and other options into a new motherboard for the ECU shows that the issue might be related to the software side of the replacement parts. It's important to work with a specialist who understands the coding intricacies of Porsche vehicles, ensuring that all features are properly recognized and functioning.
   
3. Wiring Harness: The mention of a wiring harness being involved and the ECU getting "burned" suggests a potential electrical issue. Ensuring that the wiring harness is in good condition and properly connected is essential. Any damaged or incorrect wiring could lead to malfunctions in various systems.
   
4. Diagnostic Tools: Using advanced diagnostic tools specific to Porsche vehicles can help identify the root cause of the problems. These tools can provide more detailed information about the faults and aid in troubleshooting the electrical and mechanical components.
   
5. Expert Opinion: Considering the complexity of the issues you've encountered, seeking the opinion of a Porsche dealership or an experienced Porsche specialist might be beneficial. They may have access to the latest technical information and expertise in dealing with intricate problems.
   
6. Documentation: Keep a detailed record of the issues, the attempted solutions, and any changes observed in the vehicle's behavior. This information can be valuable for both you and any technicians working on the car.
   

It's essential to work with professionals who have experience with Porsche vehicles, especially considering the intricate systems and features they come equipped with. Remember that resolving complex issues may require patience and a thorough approach to diagnosing and addressing each component of the problem.

Dllrd23

this is very on point. Do all of this.

Crozzer

I’m unsure if they can help, but you might consider contacting ECUdoctors.

they commonly replace ELV (steering lock) or change it out to an emulator, and may be able to do some coding given their deep knowledge of things.

the other thing to try would be to get your hands on a PIWIS knockoff so you can have the same coding ability as a dealer.

I am sorry you are having such a frustrating time. That sucks. IMHO get it driveable, sell, eat your loss and get a different example. I should have done that and it has been 2 years of frustration after frustration with mine.

good luck!

BigBearJoe

A good first place to start is to look at wiring harness issues. Specifically the ones under the carpeting in the drivers side foot well. My 2008 Turbo developed a lot of problems and most of them were addressed with cleaning up some damaged wires in that harness. This generation of Cayenne are notorious for wiring problems due to water getting into the cabin because of clogged drains.